Quantum dot photonic-crystal-slab nanocavities: Quality factors and lasing

Abstract

Emission linewidths of quantum dot photonic-crystal-slab nanocavities are measured as a function of temperature and fabrication parameters with low-power and high-power, cw and pulsed, nonresonant excitation. The cavity linewidth is dominated by the absorption of the ensemble of quantum dots having a density of $\ensuremath{\cong}400∕\ensuremath{\mu}{\mathrm{m}}^{2}$; above the absorption edge, the cavity linewidth broadens considerably compared with the empty cavity linewidth. Gain and lasing are seen for high-power pumping; it is estimated that only a small number of quantum dots contributes to the lasing.